High-pressure piston or reciprocating compressor



May 6, 1930. c. SCHAER 1,757,782

HIGH PRESSURE PISTON OR RECIPROCATING COMPRESSOR Filed Feb. 16, 1928 2Sheets-Shet l I Fh/ENTU R:

May 6, 1930.' c. SCHAER 1,757,782.

HIGH PRESSURE PISTON OR REQIPROCATING COMPRESSOR Filed Feb. 16, 1928 2Sheets-Sheet 2,

INVENTU R: 61% QMW BY wawxwfaw ATI'DRNEYS Patented May 6, 1930 UNI-TED'STAT'EVSVPATEN'F oFFicE GHARLES SCHAER, F LANGENTHAL, swITzER-LAEAssreivoR To THE FIRM scLzER FRERES SOCIETE ANONYJVIE, OF

INTERTH R, SWITZERLAND HIeE-rREssURE PISTON 0R RECIPROGATING OoMPRESSORI Application filed February 16, 1928, SerialNo. 254,728, and inSwitzerland October S, 1927. v

' This'invention relates to high pressure piston or reciprocatingcompressors or the like of the kind in which the driving apparatusdrives the compressor piston or intermediate piston'connected theretothrough the medium of an oscillating column of liquid.

' ings,in' which According tothepresent invention each liquid column isprovided with at least one automatically opening closure member. Theclosure member may constitute a relief valve for the escape of air fromthe liquidcolumn, or a safety device which opens when a maximumpermissible pressure is exceeded. When at least two liquid columns andmore than one valve or closure -mem ber are provided, the liquid columnsmay be connected together by valves by means of which the pressuredifference can again be correctly adjusted automatically when excessivedifferencesin pressure occurbetween the liquid columns. Preferably eachliquid column isnot' only provided with at least one closure member inthe form with at least one closure member in the form of a safetydevice. In addition atleast one of'the closure members may serve asa'feed device for the liquid column.

The invention is particularly applicable to compressors of the abovetype in which the intermediate piston, i. e. the piston which drives thecompressor piston, is exposed on both faces to the said column.

A few constructional examples of the in vention in its application to ahigh pressure reciprocating compressor are illustrated by wayof examplein the accompanying draw,-

Figure 1 showsa compressor according to the invention partly in section,and partlyin elevation, V I Figures 2, 3 and 4 show modified forms ofcompressor according to the invention, and

Figure 5 showsa detail. In the construction illustrated in Figure 1 theprimary piston 2 of the driving machine (not shown) reciprocates withina: cylinder 1 while the intermediate pistons 5 and 6 re ciprocate withincylinders 3 and 4 respec tively and actuatethe compressor pistons .7 and8. On the casings 9 and 10 are mounted The feed devices are of a reliefvalve, but also end position.

the compressor cylinders A and B. In the cylinder. spaces to the leftand right of the piston 2 are disposed the driving liquid columns I andII, whilst in the connecting meme ber 11 is enclosed a connecting liquidcolumn III. Oil is preferably used as the pressure transmitting mediumand this'is supplied to the columns III, I and II by the feed devices15, 16 and 17 respectively. Each of the chambers, containing the liquidcolumns III, I and II is'provided with a closure member in the form of asafety device 12,13 and 14 respectively and with at least one closuremember in the form of an airrelief valve 18, 18 or 19 or 20. The safetydevices may, for example, be in the form of outlet valves of knownconstruction and may terminate in a collecting pipe ora collecting tanknot shown. connected to a pressure supply pipe, or to apressure supplytank not shown. In addition to the above mentioned devices the piston 2of the driving machine is provided with valves 21 and 22 and'the pistons5-and 6 with valves 23, 24 and 25, 26 respectively, For the sake ofclearness' the valves, which are spring controlled, are shown as open inthe mid position of the piston, whilst in the dotted end positions ofthe. piston they are shown in the position which they then occupy. p 1

The displacement volume (stroke m'piston area). of the primary piston 2ofthe driving machine'is'larger than the displacement volumes oftheintermediate pistons 5 and 6 6 is limited by stops 40 and 41 and 42 and43 respectively. As a result, the intermediate plstons will reach thelimits of their strokes before the primary piston 2 has reached itsExcessively high pressures would therefore occur inthe oil columns ifmeans were not provided for controlling these pressures. According toFigure 1 this is effected by providing in each piston 2, 5

as describedabove, and so constructing these valves that whe Prgssureon-one. face and 6 two valves 21, 22 and'23, 24 and 25, 26

of the piston exceedsthat on the other face by a predetermined amount,oil can pass through. If now the piston 5 reaches the end of its strokebefore the piston 2 has reached the end of its stroke, i. e. while it isstill moving to the left, the oil, which the latter piston continues todisplace until it reaches its left hand reversing point passes throughthe valve 23 into the liquid column III", thus relieving the excesspressure. Should the piston 6 have already reached the up er end of itsstroke oil will flow from the chamber III through the valve 26 into theliquidcolumn II. The oil which has been a lost during the operation byleakages is replaced through the feed valves 15, 16 and 17. If, forexample, liquid has been lost from the column I through the stuflingboxes, the piston 5 will reach the stop limiting the upward strokebefore the piston 2 has reached the end of its stroke to the right. Avacuum would therefore be produced on the lefthand side of the piston 2in the liquid column I if the oil were not automatically replacedthrough the valve 16 which, during a predetermined portion of the strokehas a'higher pressure than the liquid column itself. The replacementofoil in the oil columns II and III is efl'ected'ina similar manner.

If an extremelyrapid'adjustment is required to avoid large increases inpressure,

closure members 12, 13 and 14: in the form of 7 safety valves, areprovided. The valves 21 to- 26 are not absolutely essential as theirpurpose can be fulfilled by the safety devices 12,113 and 14.. I

The construction shown in Figure2 differs from that shown in Figure 1 inthat two feedrvalves 15 are provided for the connecting liquid columnIII. One of these, for" example, the left-hand one, supplies pressuretransmitting liquid of normal pressure when the. device isinoperative,vwhile the righthand one-supplies liquid at increasedpressure. The piston 2 of the driving machine and the intermediatepistons 5 and 6are not 7 provided with valves in this construction.

In place thereof there is providedan automatically opening closuremember which acts as a by-pass device. The liquid column I is connectedby the valve 27 and the bypass pipe 28 tothe coupling liquid column III,whilst the liquid column II is connected to.

the liquid column III by the valve 29 and the bypass pipe 30.

In accordance with the method of construction adopted, the displacementvolume of the piston 2 is larger than that of the pistons 5 and 6;thelatter therefore reach the limits of their strokes before the piston2 has. reached itsdead point positions. If an excess pressure nowoccurs, for example in the 'columnI relatively to the column III,

this pressure will be adjusted by a correspending "discharge through theoverflow Figure 3' hows an application to a compressor 1n which theconnecting liquid column is located above the piston 2 of the drivingmachine and in this case separate. by-passmembers, or piston, valves ofequivalent action are not provided. For the purpose ofreplenishing allthree columns, feed valves 15, 16 and 17 are, however, provided and inaddition to the closure members 18, 18, 19

and 20, formed as air escape valves, there are provided safety valves12, 13 and 14 which open is exceeded. fIf during" the operation too muchoil is present in any column for any reason,it can flow out through thesafety when almaximum permissible pressure 7 valves, also a deficiencyin oil isjimmediately made up when the pressure in one of the columnshas been reduced to a value below that of the replenishing oil.

' In order to avoid shocks, or knocking, the intermediate pistons 5 and6 may also be provided with extensionsld a'nd'45-which in theneighbourhood of the dead point engage with a stop,such for example'as43 or 40,to limit their stroke, in such a manner that the liquiddisplaced by the pistons is throttled. In this manner the movement ofthe pistons 5 and 6is retardedtowards the end of the stroke and theycomeinto contact with an oil cushion 17 as isindicated by dottedlines-in the case of the driving piston 6-shown in Figure 5. V

In the single stage compressor illustrated in Figure 4, twofeed valves31 and 32,- and two equalizing valves 36 and 37 are provided foradjusting thepressure in the liquid columns, an air relief valve38'beingprovided {for theliquid column'I. Similarly the coL umn II hastwo air relief valves 39 and 4 6 and each column has a safety valve 33and 34;

These only come .into operation when the pressure in the liquid columnsexceeds a predetermined amount, for example should the valves 36 and 37fail. The method of opera- 7 tion corresponds with that of the pistonmachines previously described. If desired, the air relief valve-may be.connected to a. safety device. i

I claim:

1. Ina high pressure reciprocating compressor, the combination withaprimary-piston effecting a positive movement, ofatle'astone intermediatepiston, a'compressor piston connected to said intermediate piston, anoscillating column of liquid between said primary and intermediatepistons, means for supplying liquid to said liquid column, and means forallowing the escape of air from said liquid column.

2. In a high pressure reciprocating compressor, the combination with ahorizontally arranged primary piston effecting a positive.

movement, of a plurality of vertically arranged intermediate pistons, acompressor piston connected to each intermediate piston, an oscillatingcolumn of liquidbetween one side of said primary piston and one of saidintermediate pistons, a second oscillating liquid column between theother side of said primary piston andanother of said intermediatepistons, a third oscillating column of liquid between said intermediatepistons, means for supplying liquid to said liquid columns, and a airfrom each of said liquid columns.

3. In a high pressure reciprocating compressor the combination with aprimary piston effecting a positive movement, ofat least oneintermediate piston, a compressor piston connected to said intermediatepiston, an oscillating column of liquid between said primary andintermediate supplying liquid to said liquid column, a relief valve forthe escape of air from said liquid column, and a safety device whichopens when a maximum permissible pressure in said liquid column isexceeded.

4:. In a high pressure reciprocating compressor the combination with ahorizontally arranged primary piston effecting a positive movement, of aplurality of vertically arranged intermediate pistons, a compressorpiston connected to each intermediate piston, an oscillating column ofliquid between'one side of said primary piston andone of saidintermediate pistons, liquid column between the other side of saidprimary piston and another of said inter mediate pistons, a thirdoscillating column of liquid between said intermediate pistons, meansfor supplying liquid to said liquid columns, a relief valve for theescape of air from each of said liquid columns, and a safety devicewhich opens when a maximum permlssible exceeded.

In testimony whereof I have affixed my signature. 7

CHARLES SOHAER.

pressure in said liquid columns is relief valve for the escape of Ypistons, means fora second oscillating

